Demystifying a Wireless Network

Thursday Feb 28th 2008 by Joseph Moran
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In Part 1, we looked the basic components of a network and how they all fit together. In this article, we examine wireless networking, and how it can provide flexibility while cutting costs.

In Part 1 of our small-business networking story, we talked about the various parts that comprise a basic network. Now it's time to discuss a wireless network (or WLAN, for Wireless Local Area Network), which serves the same purpose as a wired one: to link a group of computers. Because a wireless doesn’t require costly wiring, the main benefit is that it's generally easier, faster and cheaper to set up.

By comparison, creating a network by pulling wires throughout the walls and ceilings of an office can be labor-intensive and thus quite expensive. But even when you have a wired network already in place, a wireless network can be a cost-effective way to expand or augment it. In fact, there’s really no such thing as purely wireless network, because most link back to a wired network at some point.

Another major benefit of a wireless network is that it can provide employees with mobility around the office. It lets workers equipped with notebooks or handhelds a wireless network allows to stay connected from wherever they happen to be-- or even while moving around -- rather than being tethered to the network jack on an office or cubicle wall.

The Basics
Wireless networks operate using RF, or radio frequency, technology. When you tune your car stereo to your favorite oldies station, the stereo receives the signal that station transmits. Wireless networks work according to a similar principle, so one way to think of computers on a wireless network is as a group of radio stations in close proximity transmitting digital data rather than audio, and where every “station” is able to receive as well as transmit. 

The cornerstone of a wireless network is a device known as an access point (or AP for short). The primary job of an access point is to broadcast a wireless signal that computers can detect and “tune” into. As we mentioned earlier, wireless networks are usually connected to wired ones, so an access point also often serves as a link to the resources available on the a wired network, such as an organization’s Internet connection.

In order to connect to an access point and join a wireless network, computers must be equipped with their own radios, also known as wireless network adapters. These are often built right into the computer-- especially notebooks or other portables—but just about any computer can be made wireless-capable through the use of an add-on adapter plugged into an empty expansion slot, USB port, or in the case of notebooks, a PC Card slot.

Wireless Technology Standards
Because there are multiple technology standards for wireless networking, it pays to do your homework before buying any equipment.

The first widely used wireless networking technology, known as 802.11b (more commonly called W-Fi), first debuted almost a decade ago but is still in use. In 2003, a follow-on version called 802.11g appeared offering greater performance (that is, speed and range -- more on these in a moment) and which remains today’s most common wireless networking technology.

Another improved standard called 802.11n is currently under development and is scheduled to be complete in 2009. But even though the 802.11n standard has yet to be finalized, you can still buy products based on the “draft” 802.11n standard, which you will be able to upgrade later to the final standard.

Compatibility
So how do you successfully navigate this alphabet soup of standards? All of the Wi-Fi variants (802.11b, g, and n products) use the same 2.4 GHz radio frequency, and as a result are designed to be compatible with each other. This means you can usually use devices based on the different standards within the same wireless network. The catch is that doing so often requires special configuration to accommodate the earlier devices, which in turn can reduce the overall performance of the network.

Moreover, wireless network hardware manufacturers sometimes use non-standard technology enhancements to increase performance. Such features may not be compatible with devices from other vendors, and may even need to be turned off when not supported by every device on the wireless network. 

The bottom line is that in an ideal scenario you’ll want all your wireless devices—the access point and all wireless-capable computers—to be using the same technology standard and to be from the same vendor whenever possible. Of course, this isn’t always possible, so just remember that mixing and matching wireless hardware, while possible, may require some tweaking and won’t always deliver the best results.

Speed
When you buy a piece of wireless network hardware, it will often quote performance figures (i.e., how fast it can transmit data) based on the type of wireless networking standard it uses, plus any added technological enhancements. The crucial thing to know about these numbers is that they’re like the miles-per-gallon ratings associated with cars—put simply, your mileage may—in fact will—vary, often considerably.

In truth, performance figures plastered on product boxes or marketing literature are almost always wildly optimistic. While the official speeds of 802.11b, 802.11g, and 802.11n networks are 11, 54, and 270 megabits per second (Mbps) respectively, these figures represent a scenario that’s simply not attainable in the real world. (It’s just like how you don’t actually get to pocket your full annual salary because of deductions for taxes and so forth.)

In a nutshell, always treat wireless network performance quotes with a high degree of skepticism. As a general rule, you should assume that in a best-case scenario you’ll get roughly one-third of the advertised performance.

It’s also worth noting that a wireless network is by definition a shared network, so the more computers you have connected to a wireless access point the less data each will be able to send and receive. It’s like when you cook for four and six people show up; everyone still gets to eat, but there’s less food to go around. (One way to improve the performance and capacity of a wireless network is to use more than one access point.)

Range
Just as a wireless network's speed can vary greatly, so too can the range. For example, 802.11b and g officially work over a distance of up to 328 feet indoors or 1,312 feet outdoors, but the key term there is “up to”. Simply put, unless you’re setting up your network on the moon, you won’t see anywhere close to those numbers.

As you might expect, the closer you are to an access point, the stronger the signal and the faster the connection speed. The range and speed you get out of wireless network will also depend on the kind of environment in which it operates. And that brings us to the subject of interference. 

Interference
Interference is an issue with any form of radio communication, and a wireless network is no exception. The potential for interference is especially great indoors, where different types of building materials (concrete, wood, drywall, metal, glass, etc.) can absorb or reflect radio waves, affecting the strength and consistency of a wireless network’s signal. Similarly, devices like microwave ovens and some cordless phones can cause interference because they operate in the same 2.4 frequency range as 802.11b/g/n networks.

You can't avoid interference entirely, but in most cases it’s not significant enough to affect the usability of the network. When it does, you can usually minimize the interference by relocating wireless networking hardware or using specialized antennas.

Data Security
In the same way that all you need to in order to pick up the local radio station is a radio, all anyone needs to detect a wireless network within nearby range is a wireless-equipped computer.

There’s no way to selectively hide the presence of your network from strangers, but you can prevent unauthorized people from connecting to it, and you can protect the data traveling across the network from prying eyes. By turning on a wireless network’s encryption feature, you can scramble the data and control access to the network.

Wireless network hardware supports several standard encryption schemes, but the most common are WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), and WPA2. Although they have similar abbreviations, they are not equivalent. For example, WEP is the oldest and least secure method and should be avoided. WPA and WPA2 are good choices, but provide better protection when you use longer and more complex passwords (all devices on a wireless network must use the same kind of encryption and be configured with the same password).

Unless you intend to provide public access to your wireless network – and put your business data and your customer's personal data at risk – you should consider encryption mandatory.

Wireless networks can help you cut costs when it comes to adding or moving employees within your office and provide flexible connection options to increase productivity. Now that you know the basics involved, you can consider whether or not a wireless network makes sense for your business.

Joe Moran spent six years as an editor and analyst with Ziff-Davis Publishing and several more as a freelance product reviewer. He's also worked in technology public relations and as a corporate IT manager, and he's currently principal of Neighborhood Techs, a technology service firm in Naples, Fla. He holds several industry certifications, including Microsoft Certified Systems Engineer (MCSE) and Cisco Certified Network Associate (CCNA).

This article was first published on SmallBusinessComputing.com.

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